JP2022160776A - Rotation angle detecting device - Google Patents

Abstract

To enhance stability of a sensor output when a power source is intermittently supplied in a configuration in which a sensor for detecting rotation of a motor rotation shaft and a controller for supplying a power source are connected by a harness.SOLUTION: A sensor unit 30 is connected to a controller 40 by a harness 35, and an intermittent power source is supplied via the harness 35. The sensor unit 30 includes: a sensor 32 that is driven by a power source supplied from the controller 40 to output a sine signal and a cosine signal according to rotation of a motor rotation shaft; an amplifier 37 for amplifying an output signal of the sensor 32 to output it as a sensor signal; voltage-dividing resistors Rd21 and Rd22 for dividing a power supply voltage supplied from the controller 40 via the harness 35; and an offset voltage output circuit 39 to which the divided voltage is input and that gives an offset voltage to the amplifier. An input terminal of the offset voltage output circuit 39 is connected to ground by a decoupling capacitor C12.SELECTED DRAWING: Figure 4

Description

The present invention relates to a rotation angle detection device.

2. Description of the Related Art Conventionally, there have been proposed sensors for detecting the rotation angle of a motor rotation shaft. A technique has also been proposed for monitoring the number of rotations of the rotating shaft of the motor while the power switch is off.
For example, in Patent Document 1 below, an MR (Magnetic Resistance) sensor that detects the angular position of an electric motor is provided, and power is intermittently supplied to the MR sensor while the ignition key is off. A steering system is described that detects the rotation of a motor.

European Patent No. 2050658

However, if such a sensor is provided separately from a controller that supplies power, and a harness is used to connect the sensor, the power supply voltage immediately after the start-up will increase when the sensor is driven by intermittent power supply. may become unstable and may become a source of electromagnetic noise, so stable sensor output may not be obtained.
The present invention improves the stability of the sensor output when intermittently supplying power to the sensor in a configuration in which a sensor that detects the rotation of a rotation shaft of a motor and a controller that supplies power are connected by a harness. With the goal.

To achieve the above object, a rotation angle detection device according to one aspect of the present invention includes: a sensor unit that outputs a sensor signal including a sine signal and a cosine signal according to rotation of a motor rotation shaft of a motor; A controller that supplies sensor power and calculates rotation angle information representing the rotation angle of the motor rotation shaft based on the sensor signal is connected to the controller and the sensor unit, and the sensor power is transmitted from the controller to the sensor unit. a harness for transmitting sensor signals to the controller.

The sensor unit is driven by a sensor power source supplied from the controller via a harness, and includes a sensor that outputs a sine signal and a cosine signal corresponding to the rotation of the motor rotating shaft, and a sensor output signal that is amplified and output as a sensor signal. a voltage dividing resistor that divides the voltage of the sensor power supply supplied from the controller through the harness; and an offset voltage output circuit that inputs the divided voltage from the connection point of the voltage dividing resistor and gives an offset voltage to the amplifier. and a decoupling capacitor connecting the input terminal of the second offset voltage output circuit and ground.
The controller includes a power management unit that supplies continuous power as the sensor power supply when the power switch is on, and intermittently supplies power as the sensor power supply when the power switch is off.

Further, a rotation angle detection device according to another aspect of the present invention includes a first sensor signal including a sine signal and a cosine signal according to rotation of a motor rotation shaft of a motor, and a sine signal according to rotation of the motor rotation shaft. and a second sensor signal containing a cosine signal; and a sensor unit that supplies power to the sensor unit and outputs rotation angle information representing the rotation angle of the motor rotation shaft based on the first sensor signal and the second sensor signal. a computing controller; a harness connecting the controller and the sensor unit; transmitting power from the controller to the sensor unit; and transmitting first and second sensor signals from the sensor unit to the controller.

The sensor unit is driven by a first sensor power supply supplied from the controller via a harness, and a first sensor that outputs a sine signal and a cosine signal according to the rotation of the motor rotating shaft, and amplifies the output signal of the first sensor. and a second sensor driven by a second sensor power supply supplied from the controller through a harness to output a sine signal and a cosine signal corresponding to the rotation of the motor rotating shaft. and a second amplifier that amplifies the output signal of the second sensor and outputs it as a second sensor signal; A first offset voltage that receives the divided voltages from the connection points of the voltage dividing resistors and the second voltage dividing resistors and the first voltage dividing resistors and the second voltage dividing resistors and gives the offset voltages to the first amplifier and the second amplifier. An output circuit, a second offset voltage output circuit, and a decoupling capacitor connecting an input terminal of the second offset voltage output circuit and ground.
The controller supplies continuous power as the first sensor power supply and the second sensor power supply when the power switch is on, and stops the supply of the first sensor power supply and the second sensor power supply when the power switch is off. It has a power management unit that intermittently supplies power as a power source.

According to the present invention, in a configuration in which a sensor that detects the rotation of a rotation shaft of a motor and a controller that supplies power are connected by a harness, the stability of the sensor output is improved when power is intermittently supplied to the sensor. can.

1 is a configuration diagram showing an outline of an example of an electric power steering device according to an embodiment; FIG. It is a figure which shows an example of a 1st sine signal, a 1st cosine signal, a 2nd sine signal, and a 2nd cosine signal. FIG. 4 is an exploded view showing an outline of an example of a sensor unit; 3 is a block diagram showing an outline of an example of circuit configuration of a sensor unit; FIG. It is a figure which shows the structural example of a controller. (a) is a diagram showing an example of the waveform of the second sensor power supply Vs2 that is intermittently output while the ignition key is off, and (b) is a diagram showing the waveform of the second sensor power supply Vs2 of (a) once. FIG. 4 is a diagram showing waveforms of intermittent outputs; 3 is a block diagram of an example of a functional configuration of a power management unit; FIG. (a) to (d) are explanatory diagrams of an example of the operation of a rotation speed detection unit, and (e) is an explanatory diagram of an example of rotation speed information. 3 is a block diagram of an example of a functional configuration of a microprocessor; FIG. (a) is a diagram showing a first sine signal sin1 and a first cosine signal cos1, (b) is a diagram showing an example of angular position information θ1, and (c) is a diagram showing a motor rotation speed Nr. , (d) is a diagram showing rotation angle information θm. It is a block diagram of an example of a functional configuration of an assist control unit.

Embodiments of the present invention will be described in detail with reference to the drawings. The embodiments of the present invention shown below exemplify devices and methods for embodying the technical idea of the present invention. are not specific to the following: Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

Hereinafter, a configuration example in the case where the rotation angle detection device of the embodiment is applied to an electric power steering device (EPS) that applies a steering assist force (assist force) to the steering mechanism of a vehicle by the rotational force of a motor will be described. explain. However, the present invention is not limited to a rotation angle detection device applied to an electric power steering device, and can be widely applied to rotation angle detection devices having a sensor that outputs a signal corresponding to the rotation of a motor rotation shaft.

(Constitution)
Please refer to FIG. Column shafts (steering shafts) 2i and 2o of the steering handle 1 are connected to tie rods 6 of steering wheels via reduction gears 3, universal joints 4A and 4B, and pinion rack mechanisms 5. FIG. The input shaft 2i and the output shaft 2o of the column shaft are
o are connected by a torsion bar (not shown) that is twisted by the deviation of the rotation angle between .

The torque sensor 10 electromagnetically measures the torsion angle of the torsion bar as the steering torque Th of the steering wheel 1 .
A motor 20 for assisting the steering force of the steering wheel 1 is connected via a reduction gear 3 to the output shaft 2o of the column shaft.

The controller 40 is an electronic control unit (ECU) that drives and controls the motor 20 . The controller 40 is supplied with the battery power Vbat from the battery 14 as a power source and receives an ignition key signal IG from the ignition key 11 as a power switch. The ignition key signal IG indicates whether the ignition key 11 is on or off.
Based on the steering torque Th detected by the torque sensor 10 and the vehicle speed Vh detected by the vehicle speed sensor 12, the controller 40 calculates a steering assist command value of the assist command using an assist map or the like. A drive current I is supplied to the motor 20 based on the steering assist command value.

The sensor unit 30 includes two sensors each outputting a sensor signal according to the rotation of the motor rotating shaft of the motor 20 .
The two sensors of the sensor unit 30 independently detect the angular position θ (θ=0 to 360 [deg]) of the motor rotation shaft, and the first sine signal sin1 of amplitude A from one sensor is A× sin θ+Voff1 and the first cosine signal cos1=A×cos θ+Voff1, and from the other sensor, the second sine signal sin2=A×sin θ+Voff2 and the second cosine signal cos2=A×cos θ+Voff2 of amplitude A are output to the controller 40, respectively. The voltages Voff1 and Voff2 are offset voltages (ie, DC components of the first sine signal sin1, the first cosine signal cos1, the second sine signal sin2, and the second cosine signal cos2). An example of the first sine signal sin1, the first cosine signal cos1, the second sine signal sin2, and the second cosine signal cos2 is shown in FIG.
The controller 40 calculates the rotation angle θm of the motor rotation shaft of the motor 20 based on the first sine signal sin1, the first cosine signal cos1, the second sine signal sin2 and the second cosine signal cos2.

The controller 40 calculates the rotation angle θo of the output shaft 2o of the column shaft based on the rotation angle θm of the motor rotation shaft of the motor 20 and the gear ratio Rg of the reduction gear 3 . The controller 40 calculates the rotation angle θi of the input shaft 2i of the column shaft, that is, the steering angle θs of the steering wheel 1, based on the rotation angle θo and the steering torque Th.

In the electric power steering apparatus having such a configuration, the steering torque Th generated by the driver's steering operation transmitted from the steering wheel 1 is detected by the torque sensor 10, and the steering assist is calculated based on the steering torque Th and the vehicle speed Vh. The motor 20 is driven and controlled by the command value, and is applied to the steering system as an assisting force (steering assisting force) for the driver's steering operation.

FIG. 3 is an exploded view showing an outline of an example of the sensor unit 30. As shown in FIG. The sensor unit 30 has a magnet 31 and a circuit board 32 .
The magnet 31 is fixed to the end 24 opposite to the output end 22 of the motor rotation shaft 21 of the motor 20 and has different magnetic poles (S pole and N pole) arranged along the circumferential direction of the motor rotation shaft 21 . is doing.

A first sensor 33 and a second sensor 33 are mounted on the circuit board 32 for outputting a first sensor signal and a second sensor signal corresponding to the rotation of the motor rotation shaft of the motor 20 by detecting the magnetic flux generated by the magnet 31 . 34.
The first sensor signal output from the first sensor 33 includes a first sine signal sin1 and a first cosine signal cos1. A second sensor signal output from the second sensor 34 includes a second sine signal sin2 and a second cosine signal cos2.

The first sensor 33 and the second sensor 34 may be, for example, MR sensors (for example, TMR (Tunnel Magneto Resistance) sensors) that detect magnetic flux.
The first sensor 33 and the second sensor 34 are arranged close to the magnet 31 that rotates together with the motor rotation shaft 21 , and detect the magnetic flux generated from the magnet 31 to detect the first sensor corresponding to the rotation of the motor rotation shaft 21 . Generate a sine signal sin1 and a first cosine signal cos1, and a second sine signal sin2 and a second cosine signal cos2, respectively.

The sensor unit 30 is formed as a separate unit from the controller 40 and connected to the controller 40 by a harness 35 . The controller 40 supplies a first sensor power supply Vs1 and a second sensor power supply Vs2 that drive the first sensor 33 and the second sensor 34 respectively to the sensor unit 30 via the harness 35 . The sensor unit 30 outputs the first sensor signal and the second sensor signal to the controller 40 via the harness 35 . The length of harness 35 may be, for example, about 10 cm.

FIG. 4 is a block diagram showing an outline of an example of the circuit configuration of the sensor unit 30. As shown in FIG. The sensor unit 30 includes a first sensor 33, a second sensor 34, a first amplifier 36, a second amplifier 37, a first offset voltage output circuit 38, a second offset voltage output circuit 39, and voltage dividing resistors. Rd11, Rd12, Rd21 and Rd22.
The first sensor power line VL1 of the first sensor power source Vs1 on the sensor unit 30 side and the second sensor power line VL2 of the second sensor power source Vs2 are connected to the first sensor power line VL1 and the second sensor power line VL2 on the harness 35 side. A first sensor power supply Vs1 and a second sensor power supply Vs2 are supplied from the controller 40, respectively. Also, the first sensor ground line GND1 and the second sensor ground line GND2 on the sensor unit 30 side are connected to a ground line (not shown) on the controller 40 side via the ground line GND on the harness 35 side.

The second sensor 34 comprises a bridge circuit 34a of magnetoresistive elements Rs21, Rs22, Rs23 and Rs24 and a bridge circuit 34b of magnetoresistive elements Rc21, Rc22, Rc23 and Rc24.
The magnetization direction of the pinned layers of the magnetoresistive elements Rs21, Rs22, Rs23 and Rs24 is shifted by 90° from the magnetization direction of the pinned layers of the magnetoresistive elements Rc21, Rc22, Rc23 and Rc24.

The connection point of the magnetoresistive elements Rs21 and Rs22 connected to the second sensor power line VL2 via the power supply terminal V2SIN, and the magnetoresistive elements Rs23 and Rs24 connected to the second sensor ground line GND2 via the ground terminal G2SIN. When the second sensor power supply Vs2 is supplied between the connection point and the second sensor power supply Vs2, a differential sine signal Ss2p representing a sine component corresponding to the rotation of the motor rotation shaft 21 is output from the output terminals SIN2P and SIN2N connected to the midpoint potential point. and Ss2n are output.
Also, the connection point of the magnetoresistive elements Rc21 and Rc22 connected to the second sensor power supply line VL2 via the power supply terminal V2COS, the magnetoresistive element Rc23 connected to the second sensor ground line GND2 via the ground terminal G2COS, When a second sensor power source Vs2 is supplied between the connection point of Rc 24 and the output terminals COS2P and COS2N connected to the midpoint potential point, a differential cosine representing a sine component corresponding to the rotation of the motor rotation shaft 21 is output. Signals Sc2p and Sc2n are output.

The first sensor 33 has the same configuration as the second sensor 34, the power terminals V1SIN and V1COS correspond to the power terminals V2SIN and V2COS, respectively, and the ground terminals G1SIN and G1COS correspond to the ground terminals G2SIN and G2COS. output terminals SIN1N, SIN1P, COS1N and COS1P correspond to output terminals SIN2N, SIN2P, COS2N and COS2P respectively; differential sine signals Ss1p and Ss1n correspond to differential sine signals Ss2p and Ss2n respectively; Dynamic cosine signals Sc1p and Sc1n correspond to differential cosine signals Sc2p and Sc2n, respectively.

The second amplifier 37 amplifies the differential sine signals Ss2p and Ss2n, applies the offset voltage Voff2 output from the second offset voltage output circuit 39, and outputs the second sine signal sin2. Further, the second cosine signal cos2 is output by amplifying the differential cosine signals Sc2p and Sc2n and applying the offset voltage Voff2.
The second amplifier 37 includes a differential amplifier 37a to which the differential sine signals Ss2p and Ss2n are respectively input to the non-inverting input terminal and the inverting input terminal, and differential cosine signals Sc2p and Sc2n to the non-inverting input terminal and the inverting input terminal. A differential amplifier 37b is provided for each input.

A second offset voltage output circuit 39 applies an offset voltage Voff2 to the non-inverting input terminals of these differential amplifiers 37a and 37b.
The second offset voltage output circuit 39 may be, for example, a voltage follower circuit having an amplifier 39a. A divided voltage obtained by dividing the second sensor power source Vs2 by the voltage dividing resistors Rd21 and Rd22 is input to the non-inverting input terminal of the amplifier 39a.
For example, the resistance values of the voltage dividing resistors Rd21 and Rd22 may be made equal to divide the second sensor power supply Vs2 1:1. In this case, the offset voltage Voff2 is half the voltage of the second sensor power supply Vs2 (Vs2/2).

The first amplifier 36 and first offset voltage circuit 38 have the same configuration as the second amplifier 37 and second offset voltage circuit 39 .
The first amplifier 36 amplifies the differential sine signals Ss1p and Ss1n, applies the offset voltage Voff1 output from the first offset voltage output circuit 38, and outputs the first sine signal sin1. Further, by amplifying the differential cosine signals Sc1p and Sc1n and applying the offset voltage Voff1, the first cosine signal cos1 is output.
The first offset voltage output circuit 38 may be, for example, a voltage follower circuit to which a divided voltage obtained by dividing the first sensor power supply Vs1 by voltage dividing resistors Rd11 and Rd12 is input. The offset voltage Voff1 may be, for example, half the voltage of the first sensor power supply Vs1 (Vs1/2).
The first sine signal sin 1 , first cosine signal cos 1 , second sine signal sin 2 and second cosine signal cos 2 are transmitted to controller 40 via harness 35 .

A configuration example of the controller 40 will be described with reference to FIG. The controller 40 includes a power management unit 50 and a microprocessor (MPU: Micro-Processing Unit) 60 .
The power management unit 50 receives the battery power supply Vbat from the battery 14 and performs power management for the sensor unit 30 and the controller 40 . The power manager 50 may be implemented as a single integrated circuit (IC) chip. For example, the power management unit 50 may be a power management IC (Power Management Integrated Circuit).

Based on the ignition key signal IG, the power supply management unit 50 selects a first sensor power supply Vs1 for driving the first sensor 33 and a second sensor power supply Vs1 for driving the second sensor 34 from power supplied from the battery 14. A power supply Vs2, a power supply Vm for driving the MPU 60 and other components of the controller 40 (hereinafter sometimes referred to as "MPU 60, etc."), and an internal power supply for driving a digital logic circuit inside the power management unit 50 Generate a power supply Vp.

The power management unit 50 supplies power Vm to the MPU 60 and the like while the ignition key 11 is on.
The power management unit 50 also supplies the first sensor power Vs1 and the second sensor power Vs2 to the first sensor 33 and the second sensor 34, respectively. While the ignition key 11 is on, the power management unit 50 supplies continuous power as the first sensor power supply Vs1 and the second sensor power supply Vs2. The voltages of the first sensor power supply Vs1 and the second sensor power supply Vs2 while the ignition key 11 is on may be, for example, a common power supply voltage Vcc1 (for example, Vcc1=5 [V]).

Further, while the ignition key 11 is on, the power management section 50 supplies the internal power supply Vp, which is continuous power, to the digital logic circuits inside the power management section 50 . For example, the voltage of the internal power supply Vp while the ignition key 11 is on may be the common power supply voltage Vcc1. That is, the voltage of the internal power supply Vp may be equal to the voltage of the second sensor power supply Vs2.

On the other hand, while the ignition key 11 is off, the power management unit 50 stops supplying the first sensor power Vs1 to the first sensor 33 and the power Vm to the MPU 60 and the like.
Further, while the ignition key 11 is off, the power management unit 50 intermittently supplies electric power to the second sensor 34 as the second sensor power supply Vs2.
For example, the voltage of the second sensor power supply Vs2 intermittently supplied while the ignition key 11 is off may be the power supply voltage Vcc2 lower than the power supply voltage Vcc1. For example, the power supply voltage Vcc2 may be 3.3 [V].

FIG. 6(a) shows an example waveform of the second sensor power supply Vs2 that is intermittently output while the ignition key 11 is off.
When the ignition key 11 is off, the voltage of the second sensor power supply Vs2 becomes the power supply voltage Vcc2 during the intermittent output period of the time width Wt that comes in the output cycle T, and becomes "0" during the periods other than the intermittent output period. As will be described later, the power management unit 50 may dynamically change the output period T. FIG. The output period T may be, for example, 2.2 milliseconds to 6.6 milliseconds.

FIG. 6B is a diagram showing the waveform of one intermittent output of the second sensor power supply Vs2. The time width Wt of one output period during which the second sensor power supply Vs2 is intermittently output is the sum of the standby period Pw, the idle period Pi, and the sampling period Ps.
The standby period Pw is a period during which the sampling of the second sensor signal is prohibited in order to avoid the influence of the voltage fluctuation occurring immediately after the intermittent output of the second sensor power supply Vs2 is started on the second sensor signal of the second sensor 34. is. The standby period Pw may be, for example, a fixed value or an arbitrary value programmable in the power management unit 50 .

The period lengths of the idle period Pi and the sampling period Ps are arbitrary values programmable in the power management unit 50 . The sampling period Ps is designated as a period during which the power management unit 50 samples the second sensor signal of the second sensor 34 when the ignition key 11 is off.
The period length of the idle period Pi can be programmed to specify the start time of the sampling period Ps, and the period length of the sampling period Ps can be programmed to specify the end time of the intermittent output of the second sensor power supply Vs2.

The length of the time width Wt of the intermittent output of the second sensor power supply Vs2 affects the dark current flowing through the sensor unit 30 and the controller 40 while the ignition key 11 is off. That is, it affects the power consumption of the sensor unit 30 and the controller 40 while the ignition key 11 is off. The longer the time width Wt, the greater the dark current and power consumption, and the shorter the time width Wt, the less the dark current and power consumption.

On the other hand, if the idle period Pi and the sampling period Ps are shortened, it becomes difficult to accurately sample the second sensor signal output from the intermittently driven second sensor 34 .
For example, when the supply of the second sensor power supply Vs2 starts, the voltage of the second sensor signal received by the controller 40 from the second sensor 34 ranges from "0" to a value corresponding to the magnetic flux applied to the second sensor 34. , changes with a certain time constant. The time constant of the second sensor signal is determined by, for example, the electrical characteristics of the second sensor 34 itself, the impedance of the harness 35 and the input circuit, and the like. Therefore, if the idle period Pi is too short, there is a risk that a signal smaller than the original second sensor signal will be sampled.

Therefore, the time width Wt of one intermittent output of the second sensor power supply Vs2 is set according to the current consumption (dark current) allowed for the sensor unit 30 and the controller 40 while the ignition key 11 is off. is desirable. For example, the time width Wt of one intermittent output of the second sensor power supply Vs2 may be 220 microseconds or less.

The time width Wt of one intermittent output of the second sensor power source Vs2 is the time constant of the second sensor signal when intermittent supply of the second sensor power source Vs2 starts while the ignition key 11 is off. It is desirable to be set according to
For example, when 100 microseconds elapse after the start of output of the second sensor power supply Vs2, the second sensor signal becomes sufficiently large (for example, when the second sensor power supply Vs2 is continuously supplied, the second sensor signal It is practically possible to design the Therefore, for example, the time width Wt of one intermittent output of the second sensor power supply Vs2 may be 100 microseconds or more.

As described above, while the ignition key 11 is off, the power management unit 50 intermittently supplies electric power to the second sensor 34 as the second sensor power supply Vs2. When the second sensor power supply Vs2 is intermittently supplied to the second sensor 34 through the harness 35, a transient current flows immediately after the rise, the power supply voltage becomes unstable, and electromagnetic noise is generated. It can be a source. Therefore, the second sensor signal obtained from the second sensor 34 may become unstable while the ignition key 11 is off.

Therefore, a bypass capacitor and a decoupling capacitor are provided in the second sensor power supply line VL2 of the second sensor power supply Vs2. Bypass capacitors mainly function to release relatively high-frequency noise components to the ground, and decoupling capacitors mainly function to absorb relatively low-frequency voltage fluctuations and stabilize the power supply system. The same capacitor may perform both functions.
In the present invention, both when the ignition key 11 to which the second sensor power source Vs2 is continuously supplied is on and when the ignition key 11 to which the second sensor power source Vs2 is intermittently supplied is off, ( 1) Power supply stability on the second sensor 34 side, (2) good EMC (Electromagnetic Compatibility) characteristics, and (3) reduction of dark current when the ignition key 11 is off are required.
From the viewpoint of power supply stability, a decoupling capacitor with a large capacity is desired. On the other hand, when the ignition key 11 to which the second sensor power supply Vs2 is intermittently supplied is turned off, a bypass capacitor with a small capacitance is desired from the viewpoint of fast signal rise and reduction of dark current. Also, from the viewpoint of EMC characteristics, a bypass capacitor that functions in a high frequency region is desired.

By repeating simulations, the inventors discovered that a stable second sensor signal can be obtained by providing bypass capacitors and coupling capacitors at the following three locations (1) to (3).
(1) The input terminal of the second offset voltage output circuit 39 is connected to the input terminal of the second offset voltage output circuit 39 and the second sensor ground line GND2 (that is, the connection point of the voltage dividing resistors Rd21 and Rd22 and the second sensor ground line GND2). By providing a decoupling capacitor C12 (see FIG. 4) so as to connect the sensor ground line GND2, even if the second sensor power supply Vs2 is switched when the second sensor power supply Vs2 is intermittently supplied, A low-pass filter formed by a voltage dividing resistor Rd21 and a decoupling capacitor C12 cuts off voltage fluctuations due to the transient current, thereby suppressing fluctuations in the DC component of the second sensor signal. As a result, the stability of the second sensor signal can be improved.

(2) Position close to the second sensor 34 By providing bypass capacitors C23 and C24 connecting the second sensor power supply line VL2 and the second sensor ground line GND2 at a position close to the second sensor 34, the second sensor The electromagnetic noise caused by the switching of the power supply Vs2 can suppress the influence of the second sensor 34, and as a result, the stability of the second sensor signal can be improved.

(3) A position close to the power management unit 50 By providing a decoupling capacitor C32 (see FIG. 5) connecting the second sensor power line VL2 of the harness 35 and the ground line GND at a position close to the power management unit 50 , the voltage fluctuation of the power supply generated when the second sensor power supply Vs2 is switched can be suppressed from entering the harness 35, and the power supplied by the harness 35 can be stabilized. Also, noise generated from the harness 35 can be reduced.
Bypass capacitors and decoupling capacitors are connected to the above three points (1) to (3) even when the ignition key 11 is on (that is, when the second sensor power supply Vs2 is continuously supplied). By doing so, the influence of noise from the outside on the second sensor 34 can be suppressed, so the stability of the second sensor signal can be improved.

As with the second sensor power supply line VL2 of the second sensor power supply Vs2, the first sensor power supply line VL1 of the first sensor power supply Vs1 may be provided with a bypass capacitor or a decoupling capacitor. In this embodiment, a decoupling capacitor C11 (see FIG. 4) is provided to connect the input terminal of the first offset voltage output circuit 38 and the first sensor ground line GND1.
Also, bypass capacitors C21 and C22 are provided at positions close to the first sensor 33 to connect the first sensor power supply line VL1 and the first sensor ground line GND1.
Also, a decoupling capacitor C31 (see FIG. 5) connecting the first sensor power line VL1 of the harness 35 and the ground line GND is provided at a position close to the power management unit 50 .

Furthermore, a bypass capacitor Ce1 for electrostatic discharge surge (ESD) countermeasures, which connects the first sensor power supply line VL1 on the sensor unit 30 side and the first sensor ground line GND1 at a position close to the connector with the harness 35; A bypass capacitor Ce2 for ESD countermeasures may be provided that connects the second sensor power supply line VL2 on the sensor unit 30 side and the second sensor ground line GND2.

Returning to FIG. 5, the description of the controller 40 is continued. Even while the ignition key 11 is off, the power management unit 50 continuously supplies power as the internal power supply Vp. That is, the power management unit 50 supplies continuous power as the internal power supply Vp regardless of whether the ignition key 11 is on or off.
However, while the ignition key 11 is off, the power management unit 50 supplies the internal power Vp having a voltage lower than the voltage while the ignition key 11 is on.
For example, the voltage of the internal power supply Vp while the ignition key 11 is off may be equal to the power supply voltage Vcc2, which is the voltage of the second sensor power supply Vs2 while the ignition key 11 is off.

The power management unit 50 also detects the rotation speed of the motor rotating shaft 21 based on the second sine signal sin2 and the second cosine signal cos2, and generates rotation speed information representing the rotation speed. The rotational speed information includes a sine count value CNTs obtained by counting changes in the sign of the second sine signal sin2 and a cosine count value CNTc obtained by counting changes in the sign of the second cosine signal cos2. The sine count value CNTs and the cosine count value CNTc change depending on the combination of the sign of the second sine signal sin2 and the sign of the second cosine signal cos2. Details of the power management unit 50 will be described later.

Based on the steering torque Th detected by the torque sensor 10 and the vehicle speed Vh detected by the vehicle speed sensor 12, the MPU 60 calculates a steering assist command value of the assist command using an assist map or the like, and drives the motor 20. Control the current I.

The MPU 60 also calculates angular position information θ1 representing the angular position of the motor rotation shaft 21 based on the first sine signal sin1 and the first cosine signal cos1.
The angular position information θ1 represents the angular position within the angular range of one rotation of the motor rotating shaft 21 (θ1=0 to 360 [deg]).
The MPU 60 calculates rotation angle information θm representing the rotation angle of the motor rotation shaft 21 based on the rotation speed information (the sine count value CNTs and the cosine count value CNTc) generated by the power management unit 50 and the angular position information θ1. The rotation angle information θm represents the rotation angle in the multi-turn angle range of one or more rotations of the motor rotation shaft 21 .

Specifically, while the ignition key 11 is off, the supply of power Vm to the MPU 60 is stopped, so the MPU 60 stops operating.
When the ignition key 11 is turned on from off, the MPU 60 reads out the rotation speed information from the power management unit 50 and calculates the rotation angle information θm based on the rotation speed information and the angular position information θ1.
While the ignition key 11 is on, the MPU 60 calculates the angle change of the angular position information θ1 after the ignition key 11 is turned on from off to the rotation angle calculated at the time when the ignition key 11 is turned on from off. By accumulating the information .theta.m, the rotation angle information .theta.m after the ignition key 11 is turned on from off is calculated.

The MPU 60 multiplies the rotation angle information θm by the gear ratio Rg of the reduction gear 3 to calculate the rotation angle θo of the output shaft 2o of the column shaft. Further, based on the steering torque Th detected by the torque sensor 10, the torsion angle θt of the torsion bar provided on the column shaft is calculated, and the torsion angle θt is added to the rotation angle θo of the output shaft 2o to obtain the input of the column shaft. A rotation angle θi of the shaft 2i (steering angle θs of the steering wheel 1) is calculated.

The controller 40 may control the steering assist force applied to the output shaft 2o by the motor 20 based on the rotation angle information of the rotation angle θo of the output shaft 2o and the rotation angle θi of the input shaft 2i.
For example, the controller 40 may determine whether the column shaft is in the end-contact state based on the rotation angle information. When the column shaft is in the end-reliance state, the controller 40 may limit the drive current I of the motor 20 to reduce the steering assist force.

Further, for example, the controller 40 may determine whether the steering wheel 1 is in the additional steering state or the reverse steering state based on the rotation angle information. For example, the controller 40 may determine whether the vehicle is in the additional steering state or the reverse steering state based on the rotation angle of the column shaft and the direction of change thereof. The controller 40 may also determine whether the vehicle is in the additional steering state or in the reverse steering state based on the rotation angle of the column shaft and the steering torque Th.
The controller 40 increases the steering assist force by increasing the drive current I in the additional steering state, and decreases the drive current I in the reverse steering state to decrease the steering assist force. good too. Details of the MPU 60 will be further described later.

Next, an example of the functional configuration of the power management unit 50 will be described with reference to FIG. The power management unit 50 includes a regulator 51 , a first power supply unit 52 , a second power supply unit 53 , a third power supply unit 54 , a power control unit 56 and a rotation speed detection unit 58 . The third power supply section 54 is an example of the "power supply section" described in the claims.

The power control unit 56 generates an operation switching signal Sig based on the ignition key signal IG and outputs it to the regulator 51 , the first power supply unit 52 , the second power supply unit 53 and the third power supply unit 54 .
The operation switching signal Sig indicates whether the ignition key 11 is on or off. For example, the value indicating that the ignition key 11 is on may be "1", and the value indicating that the ignition key 11 is off may be "0".
Further, while the ignition key 11 is off, the power supply control unit 56 sends the timing signal St of the period T indicating the start timing of the intermittent output period of the second sensor power supply Vs2 to the third power supply unit 54 and the rotation speed detection unit. 58.

The regulator 51 generates a regulator power supply VR having a predetermined voltage from the battery power supply Vbat. The first power supply unit 52 and the second power supply unit 53 generate the power supply Vm and the first sensor power supply Vs1 from the regulator power supply VR. Further, the third power supply unit 54 generates the second sensor power supply Vs2 and the internal power supply Vp from the regulator power supply VR.
The regulator 51 switches the voltage of the regulator power supply VR according to the operation switching signal Sig.

For example, the voltage of the regulator power supply VR while the operation switching signal Sig is "0" (that is, while the ignition key 11 is off) is changed to is on)) may be lower than the voltage of the regulator power supply VR. As a result, the voltages of the second sensor power supply Vs2 and the internal power supply Vp while the ignition key 11 is off can be made lower than the voltages while the ignition key 11 is on.
For example, the voltage of the regulator power supply VR may be 6 [V] while the operation switching signal Sig is "1", and the voltage of the regulator power supply VR may be 4 [V] while the operation switching signal Sig is "0". It may be [V].

The first power supply unit 52 supplies continuous power as the power supply Vm to the MPU 60 and the like while the operation switching signal Sig is at the value “1”, and the second power supply unit 53 continuously supplies power as the first sensor power supply Vs1. power is supplied to the first sensor 33 .
Further, while the operation switching signal Sig is "1", the third power supply unit 54 supplies continuous power as the second sensor power supply Vs2 to the second sensor 34 and the rotation speed detection unit 58, and the internal power supply Continuous electric power is supplied to the rotational speed detection unit 58 as Vp.
As a result, while the ignition key 11 is on, the MPU 60, etc., the first sensor 33 and the second sensor 34 operate continuously. Also, the voltages of the first sensor power supply Vs1, the second sensor power supply Vs2, and the internal power supply Vp at this time are the power supply voltage Vcc1.

On the other hand, while the operation switching signal Sig is "0" (that is, while the ignition key 11 is off), the first power supply unit 52 and the second power supply unit 53 are connected to the power supply Vm and the first sensor power supply Vs1. stop generating . As a result, the supply of the first sensor power Vs1 to the first sensor 33 and the supply of the power Vm to the MPU 60 and the like are stopped, and the operations of the first sensor 33 and the MPU 60 and the like are stopped.

The third power supply unit 54 outputs intermittent power having the power supply voltage Vcc2 as the second sensor power supply Vs2 while the operation switching signal Sig is "0".
As a result, the second sensor power supply Vs2 with the power supply voltage Vcc2 lower than the power supply voltage Vcc1 is intermittently supplied to the second sensor 34, and the second sensor 34 operates intermittently.
The third power supply unit 54 intermittently outputs the second sensor power supply Vs2 at timing based on the timing signal St output from the power control unit 56 . In addition, the third power supply unit 54 sets the time width Wt of one intermittent output of the second sensor power supply Vs2 according to the standby period Pw, the idle period Pi pre-programmed in the power management unit 50, and the sampling period Ps. set.

Further, the third power supply unit 54 generates continuous power having the power supply voltage Vcc2 as the internal power supply Vp while the operation switching signal Sig is at the value "0". For example, the third power supply unit 54 generates continuous common power having the power supply voltage Vcc2 from the regulator power supply VR, outputs the common power as it is as the internal power supply Vp, and switches the common power to produce the second power supply. A sensor power supply Vs2 may be generated.

The rotation speed detection unit 58 detects the rotation speed of the motor rotating shaft 21 based on the second sine signal sin2 and the second cosine signal cos2, and detects the rotation speed information representing the rotation speed (that is, the sine count value CNTs and the cosine count value CNTc). While the ignition key 11 is on, the rotational speed detector 58 generates rotational speed information at a predetermined sampling period shorter than the intermittent output period T of the second sensor power source Vs2. While the ignition key 11 is off, the rotation speed detection unit 58 intermittently generates rotation speed information when the second sensor power source Vs2 is supplied to the second sensor 34 at the intermittent output cycle T.

The rotation speed detection unit 58 includes a first comparator 58a, a second comparator 58b, a sine counter 58c, and a cosine counter 58d.
The first comparator 58a operates using the second sensor power supply Vs2 as a power supply, compares the second sine signal sin2 with the threshold voltage Vr, and generates a sign signal Cs indicating the sign of the second sine signal sin2. The sign signal Cs has a logic value of '1' when the second sine signal sin2 is greater than or equal to the threshold voltage Vr, and has a logic value of '0' when the second sine signal sin2 is less than the threshold voltage Vr.

The threshold voltage Vr may be set based on the voltage of the second sensor power supply Vs2. Since the second sine signal sin2 and the second cosine signal cos2 have a DC offset component Voff2, for example, the threshold voltage Vr may be set to the offset voltage Voff2. For example, the rotational speed detection unit 58 may include a voltage dividing resistor that divides the voltage of the second sensor power supply Vs2 or the regulator power supply VR to generate the threshold voltage Vr.
The second comparator 58b operates using the second sensor power supply Vs2 as a power supply, compares the second cosine signal cos2 with the threshold voltage Vr, and generates a sign signal Cc indicating the sign of the second cosine signal cos2. The sign signal Cc has a logical value of '1' when the second cosine signal cos2 is greater than or equal to the threshold voltage Vr, and has a logical value of '0' when the second cosine signal cos2 is less than the threshold voltage Vr.

Also, while the ignition key 11 is off, the first comparator 58a and the second comparator 58b detect the second sine signal sin2 and the second cosine signal cos2 as the timing signal with the period T output from the power supply control unit 56. It is acquired within a sampling period Ps starting from a start time determined based on St, a standby period Pw, and an idle period Pi pre-programmed in the power management unit 50 . Thereby, the first comparator 58a and the second comparator 58b intermittently generate the code signals Cs and Cc while the ignition key 11 is off.

Please refer to FIGS. 8(a) and 8(b). In FIG. 8(a), the broken-line waveform shows an example of the second sine signal sin2, and the solid-line waveform shows an example of the second cosine signal cos2.
The amplitude A of the second sine signal sin2 and the second cosine signal cos2 of the embodiment is half the voltage of the second sensor power supply Vs2 (that is, Vs2/2), and the DC component is the voltage of the second sensor power supply Vs2. (ie, Vs2/2).
Therefore, the threshold voltage Vr is set to half the voltage of the second sensor power supply Vs2 (that is, Vs2/2).
For example, when the ignition key 11 is on and the second sensor power supply Vs2 is 5 [V], the threshold voltage Vr is set to 2.5 [V], the ignition key 11 is off and the second sensor power supply Vs2 is When it is 3.3 [V], the threshold voltage Vr may be set to 1.65 [V].

The sign signal Cs of the second sine signal sin2 output from the first comparator 58a has a value of "1" when the angular position of the motor rotating shaft 21 ranges from 0 [deg] to 180 [deg]. deg] to 360 [deg].
The sign signal Cc of the second cosine signal cos2 output from the second comparator 58b corresponds to the angular position of the motor rotation shaft 21 in the ranges from 0 [deg] to 90 [deg] and from 270 [deg] to 360 [deg]. , and has a value of "0" in the range from 90 [deg] to 270 [deg].

Please refer to FIG. The sine counter 58c and the cosine counter 58d operate using the internal power supply Vp as a power supply, and generate the second sine signal sin2 and the second cosine signal based on the sign signal Cs of the second sine signal sin2 and the sign signal Cc of the second cosine signal cos2. A change in combination of signs of the signal cos2 is counted to calculate a sine count value CNTs and a cosine count value CNTc.
Please refer to FIGS. 8(c) and 8(d). The sine counter 58c calculates the sine count value CNTs by counting the number of times the sign of the second sine signal sin2 changes, and the cosine counter 58d calculates the cosine count value CNTc by counting the number of times the sign of the second cosine signal cos2 changes. Calculate The sine counter 58c and the cosine counter 58d store the calculated sine count value CNTs and cosine count value CNTc in, for example, a nonvolatile memory (not shown).

Specifically, the sine counter 58c changes the value of the sign signal Cs of the second sine signal sin2 from "0" to "1" while the sign signal Cc of the second cosine signal cos2 has the value "1". Then, the sine count value CNTs is incremented by one, and when the value of the sign signal Cs of the second sine signal sin2 changes from "1" to "0", the sine count value CNTs is decremented by one.
Further, the sine counter 58c changes the value of the sign signal Cs of the second sine signal sin2 from "1" to "0" while the sign signal Cc of the second cosine signal cos2 has the value "0". When the count value CNTs is incremented by one and the value of the sign signal Cs of the second sine signal sin2 changes from "0" to "1", the sine count value CNTs is decremented by one.

The cosine counter 58d changes the value of the sign signal Cc of the second cosine signal cos2 from "0" to "1" while the sign signal Cs of the second sine signal sin2 has the value "0". CNTc is increased by one, and when the value of the sign signal Cc of the second cosine signal cos2 changes from "1" to "0", the cosine count value CNTc is decreased by one.
In addition, the cosine counter 58d changes the value of the sign signal Cc of the second cosine signal cos2 from "1" to "0" while the sign signal Cs of the second sine signal sin2 has the value "1". The count value CNTc is increased by one, and when the value of the sign signal Cc of the second cosine signal cos2 changes from "0" to "1", the cosine count value CNTc is decreased by one.

As a result, when the motor rotating shaft 21 rotates once, the sine count value CNTs and the cosine count value CNTc increase or decrease by two depending on the direction of rotation. For this reason, the sum of the sine count value CNTs and the cosine count value CNTc (hereinafter sometimes referred to as "count total value CNT") is, as shown in FIG. increases or decreases by four depending on the direction of rotation. Therefore, the combination of the sine count value CNTs and the cosine count value CNTc and the total count value CNT represent the number of revolutions in quarter revolution units. For this reason, the combination of the sine count value CNTs and the cosine count value CNTc and the total count value CNT indicate which quadrant the angular position of the motor rotation shaft 21 belongs to by dividing the rotation range of the motor rotation shaft 21 into four quadrants.
Note that the sine count value CNTs and the cosine count value CNTc in this embodiment are examples, and the rotational speed information of the present invention is not limited to the sine count value CNTs and the cosine count value CNTc. The rotation speed information may be rotation speed information representing the rotation speed in units of 1/n rotation, where n is a natural number of 2 or more.

Please refer to FIG. As described above, the power management unit 50 may dynamically change the intermittent output cycle T of the second sensor power source Vs2 while the ignition key 11 is off. For example, when the motor rotating shaft 21 rotates while the ignition key 11 is off, the motor rotating shaft 21 rotates even faster after that, and the rotation speed detection unit 58 cannot correctly detect the rotation of the motor rotating shaft 21. There is a risk. On the other hand, power consumption can be reduced by lengthening the intermittent output cycle T while the motor rotating shaft 21 continues to stop.
Therefore, for example, the power management unit 50 may shorten the intermittent output period T when detecting a change in either the second sine signal sin2 or the second cosine signal cos2. Also, the power management unit 50 may extend the intermittent output period T when the constant period of the second sine signal sin2 and the second cosine signal cos2 continues.

The configuration example of the power supply management unit 50 described with reference to FIGS. Although the second power supply unit 53 is provided, the present invention is not limited to such a configuration. The power Vm and the first sensor power Vs1 may be supplied when the ignition key 11 is on, and may be supplied from components other than the power management unit 50 if the supply is stopped when the ignition key 11 is off. .

Next, an example of the functional configuration of the MPU 60 will be described with reference to FIG. The MPU 60 includes an angular position calculator 61 , a count totalizer 62 , a rotation speed calculator 64 , a twist angle calculator 65 , a rotation angle information calculator 66 , a diagnostic unit 67 , and an assist controller 68 .
The functions of the angular position calculation unit 61, the count totalization unit 62, the rotation speed calculation unit 64, the torsion angle calculation unit 65, the rotation angle information calculation unit 66, the diagnosis unit 67, and the assist control unit 68 are stored in the memory of the MPU 60 and the controller 40. It is implemented by the MPU 60 executing a program stored in a device (for example, non-volatile memory).
The rotation angle information calculation section 66 is an example of the "rotation angle calculation section" and the "steering angle calculation section" described in the claims. The assist control section 68 is an example of the "motor control section" described in the claims.

The angular position calculator 61 inputs the first sine signal sin1 and the first cosine signal cos1, and compensates for errors (offset, amplitude difference, phase difference, etc.) contained in these signals. FIG. 10(a) shows an example of the first sine signal sin1 and the first cosine signal cos1. The angular position calculator 61 calculates angular position information θ1 representing the angular position within the angular range of one rotation of the motor rotation shaft based on the first sine signal sin1 and the first cosine signal cos1 after error compensation. (θ1=0 to 360 [deg]). An example of the angular position information θ1 is shown in FIG. 10(b).

For example, the angular position calculator 61 may calculate the angular position information θ1 based on the sum (cos1+sin1) and the difference (cos1−sin1) of the first sine signal sin1 and the first cosine signal cos1.
Similarly, the angular position calculator 61 inputs the second sine signal sin2 and the second cosine signal cos2, compensates for the error, and calculates the angular position information θ2 representing the angular position within the angular range of one rotation of the motor rotation shaft. is calculated (θ2=0 to 360 [deg]).

See FIG. The count summing unit 62 counts the sine counts from the sine counter 58c and the cosine counter 58d of the power management unit 50 at the time when the supply of the power Vm to the MPU 60 is started (that is, when the ignition key 11 is turned on from off). Read the value CNTs and the cosine count value CNTc. The count summation unit 62 adds the sine count value CNTs and the cosine count value CNTc to calculate the total count value CNT as shown in FIG. 8(e).

The rotation speed calculation unit 64 calculates the quotient obtained by dividing the total count value CNT by the natural number n as the rotation speed Nr of the motor rotation shaft. The natural number n is the number of increases and decreases in the total count value CNT per rotation of the motor rotating shaft, and in this embodiment the natural number n is "4". An example of the rotational speed Nr is shown in FIG. 10(c).
See FIG. The twist angle calculator 65 calculates the twist angle θt of the torsion bar provided on the column shaft based on the steering torque Th detected by the torque sensor 10 .

The rotation angle information calculation unit 66 calculates the rotation speed Nr calculated by the rotation speed calculation unit 64, the angular position Based on the angular position information θ1 calculated by the calculator 61, the rotation angle information θm is calculated in the multi-turn angle range of one or more rotations of the motor rotation shaft.
The rotation angle information calculator 66 calculates rotation angle information θm=(360 [deg]×rotational speed Nr)+angular position information θ1 using a multiplier 66a and an adder 66b. An example of the rotation angle information θm is shown in FIG. 10(d).

After that, while the ignition key 11 is on, the rotation angle information calculation unit 66 calculates the angle change of the angular position information θ1 after the ignition key 11 is turned on from off. By accumulating the rotation angle information .theta.m calculated when the ignition key 11 is turned on, the rotation angle information .theta.m after the ignition key 11 is turned on from off is calculated.

See FIG. The multiplier 66c multiplies the rotation angle information .theta.m by the gear ratio Rg of the reduction gear 3 to calculate the rotation angle .theta.o of the output shaft 2o of the column shaft. The adder 66d calculates the rotation angle θi of the input shaft 2i of the column shaft (the steering angle θs of the steering wheel 1) by adding the torsion angle θt of the torsion bar to the rotation angle θo. The rotation angle information calculator 66 outputs rotation angle information of the rotation angle θo and the rotation angle θi.
As described above, the rotation angle information of the rotation angle θo of the output shaft 2o and the rotation angle θi of the input shaft 2i is used by the controller 40 to determine whether the column shaft is in the end-contact state and to determine whether the steering handle 1 is turned. It can be used to determine whether it is in the increase state or in the switchback state. The controller 40 may control the steering assist force applied to the output shaft 2o by the motor 20 based on these determination results.

The diagnosis unit 67 compares the angular position information θ1 calculated based on the first sine signal sin1 and the first cosine signal cos1 with the angular position information θ2 calculated based on the second sine signal sin2 and the second cosine signal cos2. Then, an abnormality occurring in the first sensor 33 or the second sensor 34 is determined. For example, when the difference between the angular position information θ1 and the angular position information θ2 is equal to or greater than the threshold,
It is determined that an abnormality has occurred in the first sensor 33 or the second sensor 34 .
Also, the diagnosis unit 67 determines an abnormality occurring in the second sensor 34 or the rotation speed detection unit 58 based on the difference between the sine count value CNTs and the cosine count value CNTc. For example, when the difference between the sine count value CNTs and the cosine count value CNTc is 2 or more, it is determined that an abnormality has occurred in the second sensor 34 or the rotation speed detection unit 58 .
Diagnosis section 67 outputs a diagnosis signal Sd indicating the determination result to assist control section 68 .

Assist control unit 68 controls drive current I for motor 20 based on steering torque Th detected by torque sensor 10 and vehicle speed Vh detected by vehicle speed sensor 12 .
FIG. 11 shows an example of the functional configuration of the assist control section 68. As shown in FIG. The steering torque Th detected by the torque sensor 10 and the vehicle speed Vh detected by the vehicle speed sensor 12 are input to a current command value calculator 71 that calculates a current command value Iref1. The current command value calculation unit 71 calculates a current command value Iref1, which is a control target value of the current supplied to the motor 20, using an assist map or the like based on the input steering torque Th and vehicle speed Vh.

The current command value Iref1 is input to the current limiter 73 via the adder 72A, the current command value Irefm whose maximum current is limited is input to the subtractor 72B, and the deviation ΔI (= Irefm-Im) is calculated, and the deviation ΔI is input to a PI (proportional integral) control section 75 for improving steering operation characteristics. A voltage control command value Vref whose characteristics have been improved by the PI control unit 75 is input to the PWM control unit 76, and the motor 20 is PWM-driven via an inverter 77 as a driving unit. A current value Im of the motor 20 is detected by a motor current detector 78 and fed back to the subtractor 72B.

The compensating signal CM from the compensating signal generating unit 74 is added to the adding unit 72A, and the characteristics of the steering system are compensated by adding the compensating signal CM to improve convergence and inertia characteristics. . Compensation signal generator 74 adds self-aligning torque (SAT) 74-3 and inertia 74-2 at adder 74-4, and further adds convergence 74-1 to the addition result at adder 74-5. and the addition result of the adder 74-5 is used as the compensation signal CM.
See FIG. When detecting the occurrence of an abnormality based on the diagnosis signal Sd output from the diagnosis section 67, the assist control section 68 performs predetermined abnormality handling processing such as stopping the driving of the motor 20 and outputting an alarm.

(Effect of Embodiment)
(1) The rotation angle detection device of the embodiment includes a first sensor signal including a sine signal and a cosine signal according to the rotation of the motor rotation shaft 21 of the motor 20, and a sine signal and a cosine signal according to the rotation of the motor rotation shaft 21. A sensor unit 30 that outputs a second sensor signal containing a cosine signal, and a rotation angle that supplies power to the sensor unit 30 and represents the rotation angle of the motor rotation shaft 21 based on the first sensor signal and the second sensor signal. A controller 40 that calculates information, a harness that connects the controller 40 and the sensor unit 30, transmits power from the controller 40 to the sensor unit 30, and transmits a first sensor signal and a second sensor signal from the sensor unit 30 to the controller 40. 35 and .

The sensor unit 30 is driven by a first sensor power source Vs1 supplied from the controller 40 via a harness 35, and includes a first sensor 33 that outputs a sine signal and a cosine signal according to the rotation of the motor rotating shaft 21; Rotation of the motor shaft 21 is driven by a first amplifier 36 that amplifies the output signal of the sensor 33 and outputs it as a first sensor signal, and a second sensor power supply Vs2 supplied from the controller 40 via the harness 35 as a power supply. A second sensor 34 that outputs a sine signal and a cosine signal corresponding to the second sensor 34, a second amplifier 37 that amplifies the output signal of the second sensor 34 and outputs it as a second sensor signal, and a controller 40 through a harness 35. First voltage dividing resistors Rd11 and Rd12, second voltage dividing resistors Rd21 and Rd22, first voltage dividing resistors Rd11 and Rd12, and second voltage dividing resistors Rd11 and Rd12, which divide the voltages of the first sensor power supply Vs1 and the second sensor power supply Vs2, respectively. a first offset voltage output circuit 38 and a second offset voltage output circuit 39 which receive divided voltages from the connection points of the piezoresistors Rd21 and Rd22 and apply offset voltages to the first amplifier 36 and the second amplifier 37; and a decoupling capacitor C12 that connects the input terminal of the offset voltage output circuit 39 and the ground.
The controller 40 continuously supplies power as the first sensor power supply Vs1 and the second sensor power supply Vs2 when the power switch is on, and stops supplying the first sensor power supply Vs1 when the power switch is off. and a power management unit 50 that intermittently supplies power as a second sensor power supply Vs2.

By providing such a decoupling capacitor C12, when the second sensor power supply Vs2 is intermittently supplied, even if the second sensor power supply Vs2 is switched, the voltage fluctuation of the power supply due to the transient current is A low-pass filter formed by the resistor Rd21 and the decoupling capacitor C12 cuts off the fluctuation of the DC component of the second sensor signal. As a result, the stability of the second sensor signal can be improved.

(2) The sensor unit 30 may include bypass capacitors C23 and C24 that connect the power supply line of the second sensor power supply Vs2 and the ground at a position close to the second sensor 34 .
By providing such bypass capacitors C23 and C24, electromagnetic noise generated by switching of the second sensor power supply Vs2 suppresses the influence of the second sensor 34, and as a result, improves the stability of the second sensor signal. can.

(3) The controller 40 may include a decoupling capacitor C32 that connects the power supply line of the second sensor power supply Vs2 of the harness 35 and the ground at a position close to the power management unit 50 .
By providing such a decoupling capacitor C32, the voltage fluctuation of the power supply generated when the second sensor power supply Vs2 is switched is suppressed from entering the harness 35, and the power supplied by the harness 35 is stabilized. can be Also, noise generated from the harness 35 can be reduced.

(4) The sensor unit 30 may include bypass capacitors C21 and C22 that connect the power supply line of the first sensor power supply Vs1 and the ground at a position close to the first sensor 33 .
By providing such bypass capacitors C22 and C22, electromagnetic noise generated by switching of the first sensor power supply Vs1 suppresses the influence of the first sensor 33, and as a result, the stability of the first sensor signal is improved. can.

Reference Signs List 1 Steering handle 2i Column shaft (input shaft) 2o Column shaft (output shaft) 3 Reduction gear 4A, 4B Universal joint 5 Pinion rack mechanism 6 Tie rod 10 Torque sensor , 11... ignition key (power switch), 12... vehicle speed sensor, 14... battery, 20... motor, 21... motor rotating shaft, 30... sensor unit, 31... magnet, 32... circuit board, 33... first sensor, 34 2nd sensor 35 harness 36 first amplifier 37 second amplifier 38 first offset voltage output circuit 39 second offset voltage output circuit 40 controller 50 power management unit 51 Regulator 52 First power supply unit 53 Second power supply unit 54 Third power supply unit 56 Power control unit 58 Rotation speed detection unit 58a First comparator 58b Second Comparator 58c...Sine counter 58d...Cosine counter 60...Microprocessor 61...Angle position calculator 62...Count summation part 64...Rotation number calculator 65...Angle calculator 66...Rotation angle information calculator , 66a, 66c... Multipliers 66b, 66d... Adders 67... Diagnostic unit 68... Assist control unit C11, C12, C31, C32... Decoupling capacitors C21 to C24, Ce1, Ce2... Bypass capacitors

Claims (7)

a sensor unit that outputs a sensor signal containing a sine signal and a cosine signal according to the rotation of the motor rotation shaft of the motor;
a controller that supplies sensor power to the sensor unit and calculates rotation angle information representing the rotation angle of the motor rotation shaft based on the sensor signal;
a harness that connects the controller and the sensor unit, transmits the sensor power supply from the controller to the sensor unit, and transmits the sensor signal from the sensor unit to the controller;
with
The sensor unit includes a sensor that is driven by the sensor power supplied from the controller through the harness and outputs a sine signal and a cosine signal corresponding to the rotation of the motor rotation shaft, and amplifies the output signal of the sensor. a voltage dividing resistor for dividing the voltage of the sensor power source supplied from the controller through the harness; an offset voltage output circuit that applies an offset voltage to an amplifier; and a first decoupling capacitor that connects an input terminal of the offset voltage output circuit and ground,
The controller comprises a power management unit that continuously supplies power as the sensor power supply when the power switch is on, and intermittently supplies power as the sensor power supply when the power switch is off.
A rotation angle detection device characterized by: 2. The rotation angle detection device according to claim 1, wherein the sensor unit includes a bypass capacitor connecting a power supply line of the sensor power supply and a ground at a position close to the sensor. 3. The rotation according to claim 1, wherein the controller includes a second decoupling capacitor connecting a power supply line of the sensor power supply of the harness and a ground at a position close to the power management unit. Angle detector. A sensor unit that outputs a first sensor signal containing a sine signal and a cosine signal corresponding to the rotation of the motor shaft of the motor and a second sensor signal containing a sine signal and a cosine signal corresponding to the rotation of the motor shaft. When,
a controller that supplies power to the sensor unit and calculates rotation angle information representing the rotation angle of the motor rotation shaft based on the first sensor signal and the second sensor signal;
a harness that connects the controller and the sensor unit, transmits the power from the controller to the sensor unit, and transmits the first sensor signal and the second sensor signal from the sensor unit to the controller;
with
The sensor unit is driven by a first sensor power source supplied from the controller through the harness as the power source, and outputs a sine signal and a cosine signal corresponding to the rotation of the motor rotating shaft; A first amplifier that amplifies an output signal of a first sensor and outputs it as the first sensor signal; A second sensor that outputs a sine signal and a cosine signal corresponding to rotation, a second amplifier that amplifies the output signal of the second sensor and outputs it as the second sensor signal, and a signal supplied from the controller through the harness. A first voltage dividing resistor and a second voltage dividing resistor that respectively divide the voltages of the first sensor power supply and the second sensor power supply, and a connection point between the first voltage dividing resistor and the second voltage dividing resistor. a first offset voltage output circuit and a second offset voltage output circuit for receiving a divided voltage and applying offset voltages to the first amplifier and the second amplifier; and an input terminal of the second offset voltage output circuit and a ground. and a first decoupling capacitor to be connected,
The controller supplies continuous power as the first sensor power supply and the second sensor power supply when the power switch is on, and stops supplying the first sensor power supply when the power switch is off. and a power management unit that intermittently supplies power as the second sensor power supply,
A rotation angle detection device characterized by: 5. The rotation angle detection device according to claim 4, wherein the sensor unit includes a first bypass capacitor connecting a power supply line of the second sensor power supply and a ground at a position adjacent to the second sensor. . 6. The controller according to claim 4, wherein the controller includes a second decoupling capacitor that connects a power line of the second sensor power source of the harness and a ground at a position close to the power management unit. rotation angle detector. 7. The sensor unit according to any one of claims 4 to 6, wherein the sensor unit comprises a second bypass capacitor connecting a power supply line of the first sensor power supply and ground at a position close to the first sensor. The rotation angle detection device according to 1.

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